This one is a problem that I have encountered and I thought someone might be able to help.
I interfaced a ADC0809 with the parallel port of the computer working with operating system Win98. The start of conversion (SOC) pulse is sent by the program which then waits for the End of conversion (EOC) from the ADC. When the ADC responds with EOC, the 8 bit data is read.
So far so good. Now if the program is put into a loop a 50ms delay has to be given before sending the second SOC. If less delay is given the data given by the ADC is zero. If 50ms delay is given the card captures sine, trianglur and square waves very well of frequency 1-2Hz.
(50ms delay corresponds to 20Hz sampling and since I demanded 10 data per cycle, I capture 2Hz waves)
Datasheet of ADC0809 says this delay is not required and the sampling frequency is 100KHz. However, I dont get this. I wrote to National semiconductors and they are of no help. After initial enquiries when they realised trouble, they just stopped communicating.
I have looked up the net and dont see anyone else talking of this problem. So please help!!!!
Best if you mail it at snipped-for-privacy@yahoo.co.in or/and snipped-for-privacy@gmail.com
bye for now Arun